Electrical circuit interrupter



July 5, 1932- F. a sHoEMAkER ET AL 1,355,492

ELECTRICAL CIRCUIT INTERRUPTER Filed June 16, 1926 Patented July 1932PATENT OFFICE FRED GLEN SHOEMAKEB AND JOHN t1. ROSE, OF DAYTON, OHIOELECTRICAL CIRCUIT INTERBUPTEB Application filed June 16,

This invention relates to electrical circuit interrupters as used forexample in breaking the circuit on the primary side in high tensionignition sets.

- The primary object of the invention is the provision of ar. electricalcircuit interrupter in which the contacts are mounted in permanentalignment with one another, both being permanently mounted in positionon a support, one of the contacts being mounted on a cantilever leafspring attached at its end to the support. The support is bodily movablein relation to the axis of a rotating cam memher which effects make andbreak action of 1 the contacts. This adjustment permits a change in theperiod or amount of opening or separation of the contacts. The contactsare opened or separated by means of a lifter or rubbing block which isforced to rub against the cam by means of a leaf spring on the end ofwhich the rubbing block is permanent ly mounted. This leaf spring isattached at its anchored end to the support in such a manner that it maybe adjusted in relation to the support and fixed in any position ofadjustment in a rigid manner.

A further object of the invention is the provision of means for rotatingthe mounting block upon which the contact support is mounted to vary thetiming or the moment of i nition with relation to the engine cranksha t,in conjunction with the manual adjustment or setting of-the support onthe mounting block, to vary the amount of opening or separation of thecontacts.

For dual ignition two separate contact a's-v semblies are provided onthe same mounting block so as to engage a single cain. In order toproperly time the moment the contacts separate in the two separateassembliesso that they are properly interrelated, the two lifter orrubbing block springs are independentlv adjustable so that the tworubbing blocks may be aligned through the center of the cam to operatesimultaneously or may be moved to any desired distance away from such acentral line in order to cause the separation of the two sets ofcontacts'at the de-' sired instants in succession. A further object ofthe invention is the pro- 1926. Serial N0. 116,360.

vision of a. reference mark, surface or line upon the cam, whichcooperates with reference marks'upon the housing or mountmg block onwhich the contact supports are mounted, so that the proper timing of thecontacts may be effected and the contacts may be so adjusted and setthat the contacts may remain open through the desired angle of rotationof the cam and so that the contacts may separate at the desired instantin proper timing relation to the cam.

Other objects are the provision of an interrupter which may be easilyand cheaply con structed and assembled, and which may be operated longperiods of time without attention. Use is made of perfectly flat springswhose tension is imparted to them by the angle of the faces of theadjacent parts at the ends where the springs are in place. The variousparts are assembled together in position and are then easily and quicklymounted in place as a separate assembly.

Further objects and advantages of the invention will be more fully setforth in the claims and in the following description in which thepreferred form of the invention is referred to for purposes ofillustration. Referring mort particularly to the drawings,

Fig. 1 is a plan View of an electrical circuit interrupter showing twocontact assemblies operated by a central cam,

Fig. 2 is a central section on the line 2-2 of Fig. 1,

Fig. 3 is a perspective view showing the adjustable manner in which therubbing block spring is mounted on the angle support block,

Fig. 4 is a side elevation of the contact assembly looking at thelifting or rubbing block spring, and

Fig. 5 is a plan view of a modified form of contact assembly in whichboth of the contacts are mounted on spring arms.

Referring more particularly to the drawing by reference numerals, afour-lobed cam l is mounted on a suitable shaft 2 and the drum-shapedmounting block 3 is rotatably mounted in a suitable housin or support 4.This mounting block 3 has a ousing or rim 5 surrounding the cam and theplate 6 forms a back of the housing and serves as a mount 9 for thecontact assemblies designated generally 7 and 8. The plate 6 is providedwith two grooves 9 and 10 within which neatly fit the two angle supportmembers 11 of the assemblies 7 and 8.

Each contact assembly has its various parts attached fixably togetherand the cantilever leaf springs employed permit the parts of theassembly to be joined together in a pivotless manner. The angle contactsupport member 11 has an arm 12 which extends 1aterally away from thebottom face 13 of the member. Permanently attached at the end of therigid arm 12 is a contact 14 and mounted in permanent alignmenttherewith so that their relationship cannot be changed is a secondcontact 15. The contact 15 is mounted permanently at the center ofpercussion of a cantilever leaf spring 16 which is fixed at one end ofthe member 11. Between arm 12 and the fixed end 17 of the spring 16 isan insulating block 18 and a second insulating strip 19 is placed on theother side of the spring. An electrical conductor 20 has its endconnected to an electrical lug 21 made of conducting material and placedin contact with the end of the spring. The housing block 6 is of coursegrounded. These various parts of the contact assembly are allpermanently and rigidly attached together by means of rivets or screws22 extending through insulating bushings 23.

One face of the insulating blocks 19 and 18 is angularly positioned inrelation to the other face so that a fiat leaf spring 16 may be used.The tension of the spring is imparted by reason of the angular positionof the face of the insulating blocks, it being understood that thespring 16 is preferably flat before assuming its assembled position.

The contacts 14 and 15 are separated by means of a rubbing block 24which is engageable with the outer portion of the spring 16 so as tomove the movable contact 15 away from the fixed contact 14 as the cam 1revolves. The rubbing block 24 is fixed to the end of a cantilever leafspring 25 by means of suitable rivets 26. The end of the steel spring 25is riveted permanently to the face 27 of an angle block 28 by means ofthe rivets 29. The face of the angle block which contacts with thespring 25 is at such an angle as shown, that the rubbing block 24 willbe forced to remain in engagement and rub on cam l as the cam rotates.This permits a flat spring 25 to be used and have the tension impartedto it by reason of the angle of the face of the angle block.

The rubbing block 24 is made of suitable insulating material such asfiber and of such size as to provide a space 30 between it and thespring16, when the rubbing block is in engagement with the lowest portion ofthe cam.

The angle piece 28 is adj ustably mounted on the member 11, beingprovided with slot 31 through which screws 32 extend, the screws beingthreaded into the bottom leg 13 of the block 11. The slots 31 extendlaterally so as to permit the rubbing block to be moved to the right orleft from its position shown in Fig. 1. The entire assembly may be movedrectilinearly so as to adjust the amount of separation of the contactsbut without disturbing their relation one to the other. This isaccomplished by the provision of the elongated slots 33 in the face 13of the contact support. Adjusting and locking screws 34 extend throughthese slots and attach to the plate 6.

The two contact assemblies 7 and 8 are identical in all respects and thepreceding description may apply to either of these assemblies. The twoassemblies are preferably mounted on opposite sides of the cam as shownand both assemblies are rotatable in unison and to equal degrees whenthe mounting block is rotated about the axis of cam 1. This isaccomplished by means of a manually operated rod 35 which is attached tothe end of the projecting lug 36 of the housing 3 and by means of whichthe ignition is advanced or retarded in relation to the camshaft.

In order to properly time the moment when the two contacts of oneassembly separate, a lamp with a battery in series may be temporarilyconnected to the lug 21 and grounded to the mounting block 6 so thatwhen the circuit is broken by the separation of the contacts 14 and 15the lamp will go out at the instant that-the contacts are separated andwill again be lighted the instant the contacts are again closed. Inorder to determine when the contact assembly is in its proper relationto the cam, an index line or groove 37 or an equivalent surface flat isprovided on the end side of the cam 1. Reference markings are providedon the rim 3 of the housing or mounting block, a suitable mark beingprovided at 38 which will indicate that the contact assembly is properlylocated if the contacts open when the line 37 is aligned with thereference mark 38. A reference mark 39 is also provided to show when thecontacts should close with the contact assembly properly positioned.

In Fig. 5 is shown a modification of the invention in which the contact40 is mounted on a cantilever leaf spring 41 which is anchored at itsinner end by the rivets 42 to the rigid arm 43 integral with the plate44, the arm 43 and plate 44 corresponding to the parts 12 and 13 of thesupport 11. The contact spring 41 is prevented from having anyconsiderable movement by the rigid arm or plate 45 which forms alimiting stop for the downward movement of the spring 41 and permitsthis spring only a slight limited movement. The upward movement of thespring is very small from the position shown in Fig. due to the smalldistance to the end of the rigid arm 43. The slight limited movement ofthe contact 40in a substantially vertical direction produces a slightrubbinga sli ht rubbing between the two contacts whic may be madesuflicient to. keep the contact surfaces clean and smooth at all timesand prevent or reduce the pittin effect of the electric are on thecontacts. he contacts may have their working surfaces horizontal orarranged in an inclined plane.

The operation of the electrical circuit interrupter is as follows: Thecam 1 rotates in a clock-wise direction and as it does so the rubbingblocks move up and down and follow the cam, against which they areforced to bear by reason of the tension imparted by the springs on whichthey are mounted! This rubbing block is engageable with the spring 16 ata point close to the contact15 after the camhas rotated a slight amountfrom the position shown in Fig. 1. When the rubbing block 24 is movedupwardly a distance equal to the space 30, the rubbing block will strikethe sprlng and cause the separation of the contacts. The spring 16 withthe contact 15 thereon may be made very light since the rubbing block isnot attached to the spring 16, and the impact of the rubbing blockagainst the spring 16 will be very small thuscausing a minimum of wearon the rubbingand contacting surfaces of the interrupter. The smallmassof the moving contact spring permits a comparatively light contactspring pressure.

at closing is due to this small mass alone. The natural period ofvibration of the moving contact spring 16 can be easily kept above thenormal operating speeds required for ignition of internal combustionengines without introducing high spring tension with resulting highcontact pressure. Furthermore, the mounting of the contact 15 atthecenter of percussion of spring 16 prevents any tendency for thecontacts to rock ,when they close. The lifter or rubbing block isalready in motion when the contact spring is struck and a rapidseparation of the contacts is ob-,

tained without accelerating all of the moving parts at the, same instantand without int-roducing high impact loads on the cam, rubbing block, orcontact spring. p

The tensions of the springs 16 and 25 are suchthat the rubbingblock andcontact spring follow the movement imparted by the cam even at very highspeeds. The space 30 permits a complete closure of the contacts andfurthermore permits a quick opening of the contacts. The two contacts 14and 15 being mounted in permanent alignment with one another in apivotless manner will insure the The impact load on the contacts.

rigid arm. This-pitting, however, does not disturb the action of thecontacts since the faces of the contacts, even when pitted, fit neatlyinto one another. This pitting effect may be removed or reduced by theconstruction shown in Fig. 5 by mounting the contacts so that they mayrub slightly one on the other.

When used with dual ignition it is often preferred to fire the sparkplugs on the intake side of the engine several degrees ahead of those onthe exhaust side. In order to permit the exact timing of the breaking ofthe contacts of the two contact assemblies, the varlousad ustmentsdescribed are provided.

The breaker assembly is adjusted vertically (see Fig. 1) by means of thefastening screws 34' so as to glvethe correct angularmovement of the camwhile the contacts remain open or separated. The contact should openwhen the index line 37 points to the reference 38 and should close whenthe line 37 points to the reference 39. This will ordinarily perrnit thecontacts to remain open for about it)" of travel of a four-lobed cam.After the two contact assemblies have been adjusted vertically so thatthe contacts remain open the desired interval in relation to the camtravel, the rubbing block 24 is adjusted to right or left by means ofthe screws'32 so that the contacts may be opened slightly sooner orslightly later in relation to the cam position.

This will not materially disturb the angular interval during which thecontacts remain open but will change the time at which this lnterval"occurs in'relation to the cam. The

two contact assemblies may therefore be.

made -to operate so that one pair of contacts opens several degreesahead of the other pair.

The spark plugs on the intake side may theres fore be made to operatethe proper angular interval ahead of the plugs on the exhaust, side ofthe engine. It has been found desirable to adjust the breaker assembliesso that the contacts open .006" to .01".- The rubbing block or lifterpreferably moves between ".02 and .03.- The rubbing block spring ispreferably adjustably mounted on the contact assembly when two breakerassemblies are used in conjunction, as. shown, so that they may,

be properly timed together, although obviously-they need not necessarilybe adjustably mounted on the breaker assembly unless such adjustment isdesirable.

We are aware that various changes and modifications may be made withoutdeparting from the spirit or scope of our invention and we do not intendto be limited to the construction herein chosen for purposes ofillustration but define our invention in the following claims.

1. An electrical circuit interrupter comprising a pair of make and breakcontacts, a contact support on which said contacts are mounted inpermanently fixed facial relation when contacting with each other, meansfor effecting make and break action of said contacts, and means foradjusting said support to bodily move said contacts rectilinearlyequally and simultaneously without disturbing their facial relation oneto the other to obtaina predetermined extent of separation or dwell ofsaid contacts at a predetermined instant in the proper timing relationof said cam.

2. An electrical circuit interrupter comprising a pair of make and breakcontacts, a contact support on which said contacts are mounted inpermanently fixed facial relation when contacting with each other, aleaf spring fastened at one end rigidly to said support and having oneof said contacts mounted directly thereon at substantially the center ofpercussion of said spring, means independent of and engageable with saidspring adjacent to said contact for effecting make and break action ofsaid contacts.

3. An electrical circuit interrupter comprising a pair of make and breakcontacts, a contact support on which one of said contacts is mountedpermanently in position, a spring fixed to said support and bearing theother contact at its free end in permanently fixed facial relation whencontacting with the other contact and means for adjusting said contactsupports rectilinearly, equally and simultaneously without disturbingtheirfacial relation one to another to obtain a predetermined extent ofseparation or dwell of said contacts at a predetermined instant in theproper timing relation of said cam.

4. An electrical circuit interrupter comprising a pair ofmake and breakcontacts, a contact support on which one of said contacts is mounted, aspring fixed to said support and bearing the other contact at its freeerid in permanently fixed facial relation when contacting with the firstcontact, rotatable means for moving said spring and effecting make andbreak action of said contacts, means for adjusting said support inrelation to the axis of the rotatable means, and means for bodily movingsaid support rectilinearly to simultaneously move said contacts withoutdisturbing their relation one to the other.

5. An electrical circuit interrupter comprising a pair of make and breakcontacts,

a contact support on which one of said contacts is mounted, a springfixed to said support and bearing the other contact at its free end inpermanently fixed facial relation when contacting with the firstcontact, rotatable means for effecting make and break action of saidcontacts, means for adjusting said support in relation to the axis ofthe rotatable means, a mounting block, means for moving said support onsaid block to simultaneously move said contacts without disturbing theirrelation one to the other, and means for rotating said mounting block tovary the time of making and breaking of the contacts.

6. An electrical timer of the class described, comprising a pair of makeand break contacts, a contact support on which one contact is fixed, aleaf spring fixed at one end to said support and bearing the othercontact thereon in alignment with said first contact, a rotatable cammember, a rubbing block bearing on said cam member and engaging saidspring to lift the spring and relatively move the contacts, a leafspring fixed to said support and bearing said rubbing block permanentlythereon at its end, and operating to maintain said rubbing block inengagement with said cam, and a mounting block to which said support isadjustably fastened.

7. An electrical circuit interrupter comprising a pair of relativelymovable contacts, a contact support on which one contact is fixed, aspring fixed at one end to said support and bearing the other contactfixed thereon, a rotatable cam member at one side of said support, arubbing block bearing on said cam member and engageable with said springto lift the spring to relatively move the contacts, a spring fixed tosaid support and bearing said rubbing block, a mounting block, a meansfor securing said support in an adjustable manner fast to said mountingblock for varying the amount of opening of the contacts, and means forrotatin said mounting block to vary the time of the making of thecontacts.

8. An electrical timer of the class described, comprising, incombination, a pair of separable contacts, a rigid contact support onwhich said contacts are mounted, a cantilever leaf spring rigidly fixedat one end to said support and bearing one of said contacts fixedpermanently thereon, a rotatable cam, a

rubbing block between the cam and the free end of said spring, a secondcantilever leaf spring rigidly attached at one end to said support andcarrying said rubbing block at its free end, said second leaf springacting.

to maintain said rubbing block on said cam, a mounting block rotatablymounted about the cam axis, and means for adjusting and rigidlyattaching said support for rectilinear movement on said mounting blockso the said contacts may be bodily moved together without disturbingthem in'relation to each other.

9. An electrical timer of the class described, comprising, incombination, a pair of elec-' trical contacts, a rigid contact supportfor said contacts, a cantilever leaf spring rigidly fixed at one end tosaid support and bearing one of said contacts fixed permanently thereon,a rotatable cam, a rubbing block between the cam and the free end ofsaid spring, a second cantilever leafspringrigidlyattached at one end tosaid support and carrying said rubbing block at its free end, saidsecond leaf spring acting to maintain said rubbing block on said cam, amounting block, and means for adjusting and rigidly attaching saidsupport for movement on said mounting block so the said contacts may bebodily moved together wifihout disturbing them in relation to each 0ter.

10. In an electrical 'timer of the class de- 4 scribed, in combination,a pair of electrical contacts, a rigid contact support, a cantileverleaf springrigidly 'fixed at one end to said support and bearing one ofsaid contacts fixed permanently thereon at a point coincidingsubstantially with the center of percussion of the spring, a rotatablecam, a rubbing block between the cam and the free end of sa-id'spring, asecond cantilever leaf spring rigidly attached at one end to saidsupport and carrying said rubbing blockat its free end, said second leafspring acting to maintain said rubbing block on said cam at all times,said rubbing block being spaced from said first leaf spring when in aposition closest to the cam axis, a mounting block rotatably mountedabout the cam axis, and means for adjustably and rigidly attaching saidsupport for rectilinear movement on said mounting block so that saidcontacts may be bodily moved without disturbing them in relation to eachother. a

11. An electrical circuit interrupter of the class described,comprising, in combination, a pair of make and break contacts, a cam foreffecting make and break action of said contacts, a mounting block onwhich said contacts are mounted, a reference line on the side of saidcam and reference marks on said mounting block adapted to cooperate withsaid reference line to indicate the opening and closing points of saidcontacts for a proper setting thereof.

prising a pair of make and break contacts, a contact support on whichsaid contacts are mounted in alignment with each other, a rotating camfor effecting make and break action of said contacts, means foradjusting said support to bodily move said contacts equally andsimultaneously without disturbing their relation one to the other, amounting block on which said support is adjustably mounted, a referenceline. on ,the side of said cam and reference marks on said mount 12. Anelectrical circuit interrupter coming block adapted to cooperate withsaid reference line to indicate the o ening and closing points of saidcontacts ting thereof. 1

13. In an electrical circuit interrupter as ora proper setset forth inclaim '12, a reference. line on the side of said cam and reference markson said mounting block adapted to indicate the points at which'thecontacts are just opening and just closing with the contacts properlyset, when aligned with said reference line.

14. An electrical circuit interrupter, comprising a pair of contactsupports, each su porting a pair of relatively movable ma 6 and breakcontacts, in permanent alignment I porting a pair of relatively movablemake and break contacts in permanent'alignment with each other, a camfor effecting make and break action of the contacts, a mounting block,means for independently and rectilinearly adjusting and fixing saidsupports on said block so that the contacts of a pair may be bodilymoved equally and simultaneously without disturbing their relation oneto the other, to vary the amount of separation of the contacts of thepair, and means for rotating said mounting block to vary the time ofopening of the contacts.

16. An electrical circuit interrupter, comprising a pair of make andbreak contacts having a permanently fixed facial relation whencontacting, a rotatable cam for causing make and break action of saidcontacts rectilinearly relative to said rotatable cam, and means foradjusting said contacts without disturbing their facial relation to varythe extent of separation or dwell of said contacts without changing thetiming relation of said electrical circuit interrupter.

17. An electrical circuit interrupter, comprising a pair of contactsupports, a pair of make and break contacts having a permanently fixedfacial relation when contacting mounted on each support, a cam foreffecting make and break action of said contacts, a rubbing block foreach support engaging said cam and operated thereby to make and breakthe contacts, means for adjusting a pair of contacts without disturbingtheir permanently fixed facial relation, to vary the extent ofseparation of the contacts without changing the timing relation of saidelectrical circuit interrupter, means for rotating-said supports aboutthe cam axis, and means for adjusting tion to said cam to vary the timethe contacts are opened in relation to the angular position of the cam.

18. An electrical circuit interrupter, comprising a pair of make andbreak contacts, a contact support to which one contact is permanentlyattached, a leaf spring fixed at one end to said support and bearing theother contact at its free end in permanent alignment with said firstcontact, a rotatable cam member, a rubbing block bearing on said cammember and engaging said spring to lift the spring and relatively movethe contacts, a leaf 7 spring adjustably fixed to said support andbearing said rubbing block permanently thereon at its free end andoperating to maintain said rubbing block in engagement with the cam,means for adjustably attaching said second leaf spring rigidly to saidsupport to variably locate the rubbing block in relation to the cammember, and a mounting block to which said support is adjustablyfastened in fixed position.

19. A unitary assembly adapted for electrical circuit breaker mechanismhaving means for effecting a periodic breaking of said circuit,comprising a movable contact having a permanently fixed facial relationwhen contacting with said movable contact, a fixed contact, saidassembly being adjustable as a unit rectilinearly relative to said meansto simultaneously move said contacts without disturbing their facialrelation one to another and to vary the extent of separation or dwell ofsaid contacts. v

20. A unitary assembly adapted for electrical circuit breaker mechanismhaving means for effecting a periodic breaking of said circuit,comprising a movable contact having a. permanently fixed facial relationwith said movable contact, a fixed contact and a cam actuated member forlifting said movable contact, said assembly being adjustable as a unitrectilinearly relative to said means to simultaneously move saidcontacts without disturbing their facial relation one to another and tovary the extent of Separation or dwell of said contacts. 7

21. A unitary assembly adapted for electrical circuit breaker mechanismhaving means for effecting a periodic breaking of said circuit,comprising a support, a pair of make and break contacts having apermanently fixed facial relation one to another when contacting, aspring member fixed to said support and carrying one of said contacts, arigid member fixed to said support and carrying the other of saidcontacts, said assembly being adjustable as a unit rectilinearlyrelative to said means to simultaneously move said contacts withoutdisturbing their facial relation one to another to vary the extent ofseparation or dwell of said contacts.

22. A unitary assembly adapted for elec trical lcircuit breakermechanism having means for effecting a periodic breaking of said circuitcomprising a support, a pair of make and break contacts, a spring memberfixed to said support and carrying one of said contacts, a rigid memberfixed to said support and carrying the other of said contacts, a liftingmember, and a further spring member fixed to said support and carryingsaid lifting member, said contacts being disposed intermediate of thepoint of lift and the fixed end of said first mentioned spring member.

23. In a circuit breaker a pair of contacts, a support, a spring memberfixed at one end to said support and carrying one of said contacts, arigid support for the other of said contacts, a lifting member and afurther spring member for carrying said lifting member, said contactsbeing disposed between the point of lift and the fixed end of said firstmentioned spring member.

24. A unitary assembly adapted for electrical circuit breaker mechanismhaving means for effecting a periodic breaking of said circuitcomprising a pair of make and break contacts, a rubbing block, a contactsupport on which one of said contacts is mounted, a spring fixed to saidsupport and having the other contact in fixed facial relation with saidfirst contact and a spring arm fixed to said support and bearing saidrubbing block, said assembly being adjustable as a unit to vary theextent of separation or dwell of said contacts without disturbing theirfacial relation.

25. An electric circuit interrupter comprising a pair of make and breakcontacts, rotatable means for effecting make and break action of saidcontacts, a mounting block on which said contacts are mounted, areference line on said rotatable means, and a reference mark on saidmounting block adapted to co operate with said reference line toindicate the opening point of said contacts for the proper settingthereof.

In testimony whereof we afiix our signatures.

' FRED GLEN SHOEMAKER.

JOHN J. ROSE.

v CERTIFICATE-0F CORRECTION.

Patent No. 1,866,492., July 5, 1932.

FRED! GLEN/.SHOEMAKER ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 5,lines 108 and [09, claim 16, strike out the words "rcctilinearlyrelative to said rotatable cam" and insert the same after "contacts"inline 110; page .6, lines 29 and 30, claim 19. strike out the comma andwords a fixed contact" and insert the same to follow "contact" in line27; and line 41, claim 20, strike out the comma and words a fixedcontact" and insert the same to follow "contact" in line 39; and thatthe said Letters Patent'should be read with these corrections thereinthat the same may conform to the record of the case in the PatentOffice. I

Signed and sealed this 17th day of January A. D. 1933.

Ma 0 M (Seal) I Acting Commissioner? of Patents.

